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DB9 serial cable wiring — Parallax Forums

DB9 serial cable wiring

jknightandkarrjknightandkarr Posts: 234
in Accessories
What is the wiring for the DB9 serial cable? I found this image, but not sure if its right.
NULLPINOUTDB9.jpg

I think my serial cable is bad, cause I have a Basic Stamp 2 Homework, PDB Rev B & the Propeller RPM Black modual all of which have serial ports and none of which are ever found, and tried 2 different pc's so its not the serial port, so I wanna make a test cable to see if thats the issue. Thanks

Joe

Comments

  • MrBi11MrBi11 Posts: 117
    Quick test (Xmit/recv only) is to jumper pins 2 & 3 and use a terminal program and see if the characters you type are echoed back to the display.
  • kwinnkwinn Posts: 8,697
    What you have is a null modem cable as the diagram title states, and that should work, however testing your cable as MrBi11 suggests is much easier.
  • jknightandkarrjknightandkarr Posts: 234
    I tried to locate a terminal program but no luck with the one I found. Couldn't figure it out, windows doesn't seem to come with it anymore. I am assuming that the most current versions of the BS and Propeller IDE's still have serial support?

    Joe
  • kwinnkwinn Posts: 8,697
    Try TeraTerm or Putty. If you really want hyperterm and have access to WinXP you can extract and run it.

    Original XP HyperTerminal

    If you just can’t live without the original HyperTerminal in Windows XP, you can actually extract two files from your XP installation and copy them over to Windows 7 or Vista.

    The two files you will need are hypertrm.dll and hypertrm.exe. Simply copy those files into any directory on your machine and it will work. You should be able to find hypertrm.exe in C:\Program Files\Windows NT and hypertrm.dll in C:\Windows\System32.

    If you have the Windows XP CD, you should be able to find both of these files in the i386 directory on the CD.
  • jknightandkarrjknightandkarr Posts: 234
    edited 2017-03-08 02:06
    I tried that TeraTerm, couldn't figure it out. Could those files still be on my desktop? Win 7 install over Win XP. Thanks for the help. I do know that when I tried my BS2 I did get it was either the echo or loopback as yes. I can't remember which one. Wouldn't that mean my serial port is working?

    Joe
  • jknightandkarrjknightandkarr Posts: 234
    I found the dll file but not the exe.... figures... lol

    Joe
  • kwinnkwinn Posts: 8,697
    You can test your serial port by connecting the RX pin to the TX pin. If echo is on each character sent will be received twice. Once by the echo function, once from the RX input. If the echo is off you will receive each character once, and no characters if the RX to TX jumper is removed.
  • carbonsparkcarbonspark Posts: 1

    When using the basic stamp2 use a straight thru cable. Pin 2 should go to pin 2 and pin 3 to 3.
  • guenthertguenthert Posts: 36
    The wiring scheme of the op looks ok (as a cross-over/"null-modem" cable, but see below) to me, except they forgot to mention that GND (pin 5) needs to be connected between both ends, it's not going to work without.
    carbonspark wrote: »
    When using the basic stamp2 use a straight thru cable. Pin 2 should go to pin 2 and pin 3 to 3.

    The stamp2 itself does of course have no DB9 (actually DE9, but that's nitpicking) connector, rather the development boards do (homework, board of education, more?)
    It's actually surprisingly difficult to find on Parallax' website, but eventually I found: https://www.parallax.com/product/800-00003 , which is mentioned in https://www.parallax.com/sites/default/files/downloads/28158-BASIC-Stamp-HomeWork-Board-Documentation.pdf
  • jknightandkarrjknightandkarr Posts: 234
    carbonspark wrote: »
    When using the basic stamp2 use a straight thru cable. Pin 2 should go to pin 2 and pin 3 to 3.
    Ok, I will try that. I made a cable, it works VERY rairly on the BS software, tried the Propeller IDE and nada yet, maybe short, but I will swap the 2 n 3 pin connections and see if that helps. Thanks.
    guenthert wrote: »
    The wiring scheme of the op looks ok (as a cross-over/"null-modem" cable, but see below) to me, except they forgot to mention that GND (pin 5) needs to be connected between both ends, it's not going to work without.
    carbonspark wrote: »
    When using the basic stamp2 use a straight thru cable. Pin 2 should go to pin 2 and pin 3 to 3.

    The stamp2 itself does of course have no DB9 (actually DE9, but that's nitpicking) connector, rather the development boards do (homework, board of education, more?)
    It's actually surprisingly difficult to find on Parallax' website, but eventually I found: https://www.parallax.com/product/800-00003 , which is mentioned in https://www.parallax.com/sites/default/files/downloads/28158-BASIC-Stamp-HomeWork-Board-Documentation.pdf

    I found the cable, I might need to just buy a new one, Kinda sucks having boards and can't use em...

    Joe

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